THE CODLIN MOTH IN IDAHO IN 1900. 



817 



In some cases picking the apples early to escape a coming brood is 

 practised. If the stages of the insect are known, this method may be 

 followed to much advantage. 



Eemedial Measures. 



In fighting this insect, the first question which presents itself is, In 

 what stage can the insect be best attacked, and how ? 



As a result of the work that has been done on this subject, it is evident 

 that any mixture strong enough to kill the egg will injure the tree» 

 Further work may throw more light upon this subject. 



At two periods in this stage the insect is vulnerable, and a larger 

 portion of the remedies have been used at these periods. 



After the young larvae hatch, and before they have started for the 

 centre of the apple, has long been recognised as the most vulnerable point 

 in the life of the insect. At this point spraying is a most efi'ective 

 remedial measure. 



I found that in Idaho the fruit-growers were using many kinds of 

 spraying solutions, with varying results. 



A patent mixture, composed largely of carbolic acid and coal-tar, was 

 used by some. This solution is supposed to have a smell about it that 

 keeps the moth away from the tree. The best I have seen this solution 

 do, with several excellent sprayings, in conjunction with bands, was to 

 save 66 per cent. I believe that what good effects are derived from its 

 use are due to the killing of the larvae with which it comes in contact. 



Many of the fruit-growers add an arsenite, usually Paris green, to the 

 carbolic compound. The results with this mixture are varying. 



Others have used kerosene in the arsenite, thereby combining both 

 poisonous and contact insecticide. One grower used this combination, 

 and writes me that " there are no wormy apples to be seen " (in his 

 orchard), and that the apples injured by all sources amounted to only 

 about 0'05 per cent. 



One difficulty is to get these different ingredients to mix well. Whale- 

 oil soap is used in combination with other sprays, but I could find no 

 facts in regard to the results of its use. 



By far the greater number of growers use the arsenites alone. Of 

 these arsenites Paris green is most used, in the proportion of one pound 

 to 150 gallons of water, with from one to two pounds of freshly slacked lime. 



Some are using London purple, and others are using a combination of 

 London purple and Paris green. Many are using the lime arsenite with 

 excellent results. In fact, wherever any of these arsenites are used 

 intelligently good results are obtained. Some growers are prejudiced 

 against certain of these arsenites on account of past experiences. In two 

 cases I found that they had omitted the lime, and in both cases the foliage 

 was badly burned. 



My observations have led me to believe that it makes but little 

 difference as to what arsenite is used if it is well applied. 



The pumps used were of all kinds and conditions. Many were using 

 nozzles which threw a coarse spray that was valueless. The time for 

 spraying is as essential as the spraying itself, and I wish that this fact 



o 



